Telephone-exchange system.



A. E.' LUNDELL.

ATsLEPHoNE EXCHANGE sYsrEM.

APPLICATION FILED NOV.13. |916.

Patented July 2, 1918.

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ALBEN E. LUNDELL, E N'EWTOEE, N. Y., AssIeNoE To wEsTEEN ELECTRIC COMPANY, i

INCORPORATED, OENEW'YCEK, VN.

Toca/whom it mag/concern:4k A, l .v y Befit known that I', ALBEN vE. LUNDELL,

Aa citizenof the United States,residing at ss f New York, in the eountyofBronx and State of New York, have --invented certain" new land useful Improvements in Telephone-Exchange Systems, of which therfollowing is full,- clear,concise,Y and exact description.

This invention relates to telephone exchange systems, and morepparticularly to telephone ysystems in which an operators telephone setf may be automatically asso- -ciatedwith a calling -subserib'ers line in response to the `extension of such line' to a link vcircuit. used in-establishing a connection,

It is the object of ythe present Ainvention nto provide means whereby thecalling party may attract an operators attention after a listening key switch operated in response to the extension of the vcalli-ng line, has been -moved into its listening-out; position.v

The drawings -disclose 'enough of a telephone' exchange system `to enableone skilled vin the art tol understand the present invention. The invention is applicable to systems of a widelyV varying'characterr but in its preferred embodiment is ladaptedfor use in' the semi-mechanical telephone system disclosed in p'atentfNo. 1,168,319.- -L ,e

subscriber-atstation A desiringjto ob- --tain a connection removes his receiverdfrom the switchhook, whereupon a line' relay 1 becomes energizedqand causes'Y the lighting of asignal 2 for attractingan operators attention.- The operator, noticing the signal llighted,inserts a plug Sinto an answering jack Itof the calling subscribers line, whereupon relays 5, 6` and an answering super- 'vi'sory krelay SR become energized .in the .well-known manner. Relay 5 disconnects `relay 1, thus causing the extinguishing of lamp 2 "ground through its armature and front contact, a Contact' 7 andthe power magnet of a listening key sequence-switch 8,l to grounded battery. Under the control of its'normal Contact. 9, the listening key vsequence switch is moved out of position 1 into its listeningin position 7. H

The operatorstelephone set 10 is now connected incircuit with the calling subscrib- -ersy station through sequence switch con- Relay 6 Closes a circuit fromv Y., A CORPORATION OF NEWT..YORK.A

I TELEPHONE-EXCHANGE SYSTEM.

n lspe'eifieatnm ofLetters Patent. Patented ,ju-lf2 1918, Application inea November 13,1916. sat1-mno.131,646. i i

tacts 11 and`12, talking battery being supplied from krepeating coil R throughV cord C. Af

v When the sequence switchS moved into position 2, a circuit was closedfrom ground, through the armature and front contacter` .relay 6, sequence switch Contact 13,5a `contact l111 andthe power magnet of a sequence ,swltch 15,7to grounded battery." Under the control j of ,y its normal Contact 16j, vthe `se- ,quencefswlt'ch 15 is movedoutlofposition l'and into position 2. kThe sequence switch 15 controls the operationof a selector switch 'byy .means of which the cord C maybe extended toward a called subscribers station ,B. Thek sequence switch 1,5 controlsl` the .association of a senderwith the selector .switch for controlling its operationin accordance with the numerical designation of the called line. The setting of the selector switch is accomplished while the .sequence kswitch 15 is resting in various positions bevmoved under the control of contacts actuated atthe sender. In the present case it will be assumed that by closing a contact 17 at the sender, thesequence switch` l15. islmoved out'of position 2 and into position 16.

f After the Callhasvbeen received, thefopercontact ofkey LO, a Contact 1.8,and ythe tween 2 to 16, in which positions it mayv be 75 'o ator depresses her listeningoutkey `[},O`,el 0s e ingrthus a circuit from' ground,- throughj theV power magnet of sequence yswitch 8, to

- grounded battery. The sequence switchis then moved into its listening-out position l11, in which positionthe telephone set 10 is disconnected from therline.

. If for any reason the operator 'desires to listen in again on an established conversation, she depresses her listening-in key LI, causing thus the energization of a relay 19. VThe relay 19 closes a locking circuit feritself through sequence switch eontact'20 kandgv its right-hand armature, and through its Ylett-hand armature ka circuit including se- -quence switch contact 21`or moving the sequence switch 8 out of position 11 and through position 12 into .positiony 1, The

relay 6 being energized atthis time, the `sequence switch 8 will be immediately moved into position 7 in the above described manner and the operators telephone set 1.0 is

ithus again Connected to thefcordC.y ,f

was standing in position 7 when the calling of position 7 and into position 11. In the' same manner, sequence switch 8 may be moved out of its listening-in position upon the closure of contact 30 of sequence switch 8. The sequence switch 8 may also' be controlled by the key LO through its contact 18.y

If the calling subscriber desiresto recall the operator afterthe connection has been established, he will momentarily depress his switchhook, causingthus the momentary denergization of relay SR: AS- suming that the sequence switch-8 is in its listening-out position 11, a circuit is closed from grounded battery, through the power magnet and contact 32 of sequence switch 8, the armature and back contact of the supervisory relay SR, and a contact 33 of the sequence switch 8 to ground. Due to .the closure of'this circuit, the sequence switch is moved into position 12, whereupon in response to the subsequent energizationof relay SR a circuit is closed from ground, through a lamp 34, the armature and front Contact of relay SR, sequence switch contact 35 and an interrupter 36,'to grounded battery. Under the control of the interrupter the'lainp is caused to flash. As soon as the operator notices the lamp flashing,

"she depresses the listening-in key LI and causes'the movement of the sequence switch 8 into position 7 in the above described manner. v

If the vlistening key sequence switch 8 subscriber caused the momentary operation of the relay SR for the purpose of recalling the operator, or if this sequence switch was in yany of the positions excepty 11, then, due to the factv that sequence switch contact 37 is closed, grounded battery is connected `through this contact and the back contact of relay SR and lamp 34 to ground, and thus the lamp 34 is caused to light up.

As soon as the, sequence switch reaches position 7 the operator will be able to converse with the calling party. If discoiinection is desired, then the calling and called subsci'ibers restore their receivers, causing thus the permanent denergization supervisory relays VSR and SR. These relays control the usual clearing-out signal for thevoperator. Lamp 34 will now be constantly lighted #and thus the operator of the knows that the calling subscriber does not want to recall her. She then removes plug 3 from jack 4, causing thus the denergization of relay 5 and 6, whereupon a circuit is closed from grounded battery, through the armature and back contact of relay 6, a contact 40, and the power magnet of sequence switch 8, to grounded battery, for moving the sequence switch outl of position 11: and through position 12 into position 1. A circuit is then closed from grounded battery, through the armature and back contact of yrelay 6, a sequence switch contact 441, a contact 42 and the power magnet of sequence switch 15, to grounded battery, for moving this sequence switch. into its normal position.

What is `claimed is:

e l. In a telephone exchange system, a line, a trunk, means for extending said line to said trunk, a variably operable switching 'device having a listening-in and a listening-out position, a signal, means operated upon the extension of said line to said trunk for moving said switching device into the listening-in position, means for moving said switching device into the listeningout position, means for moving said switching device out of said listening-out position, and means operative thereupon for actuating said signal. 2. Ina telephone exchange system, a subscribers line, an operators trunk circuit, means for extending the line to said trunk circuit, "a variably operable switching device having a listening-in and a listeningout position, means responsive to the extension of said line for moving said device into the listening-in position, means for moving said device into the listening-out position, operator controlled means for moving said device out of said listening-out position, and subscriber controlled means for moving said device out of the listeningout position. f

3, In a telephone exchange system, a

ksubscribers line, anoperators trunk circuit, means for extending said line to said circuit, a listening key switch movable to a listening-iii and listening-out position, a signal associated with the trunk, operator controlled means for moving said switch out of the listening-out position, subscriber controlled means for moving said switch out of tlielistening-out position, means controlled by said switch when moved out of lthe listeiiing-out position foractuating said signal, said last mentioned means operative only when said subscriber trolled means is actuated.

4. In la telephone exchange system, a line, a trunk, a calling signal associated with said line, operator-controlled means for eX- being conytending, the line when calling to said trunk, a recall signal at said trunk, a variably operable switching device associated with said trunk and having a normal, a listening-in and a listening-out position, means for moving said switching device into said listening-in position in response to the extension of said line to said trunk, manually operable means for moving said switching device from its listening-in to its listening-out position, and means controllable through the calling line to operate 10 said switching device for actuating said recall signal. l

In Witness whereof, I hereunto subscribe my name this 11th day of November, A. D.

ALBEN E. LUNDELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

